Messages in this thread Patch in this message | | | Date | Mon, 13 Apr 2020 11:52:34 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH v4] MIPS: Truncate link address into 32bit for 32bit kernel |
| |
Hi Jiaxun,
On Mon, Apr 13, 2020 at 02:26:49PM +0800, Jiaxun Yang wrote: > LLD failed to link vmlinux with 64bit load address for 32bit ELF > while bfd will strip 64bit address into 32bit silently. > To fix LLD build, we should truncate load address provided by platform > into 32bit for 32bit kernel. > > Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> > Link: https://github.com/ClangBuiltLinux/linux/issues/786 > Link: https://sourceware.org/bugzilla/show_bug.cgi?id=25784 > Cc: Fangrui Song <maskray@google.com> > Cc: Nathan Chancellor <natechancellor@gmail.com> > -- > V2: Take MaskRay's shell magic. > > V3: After spent an hour on dealing with special character issue in > Makefile, I gave up to do shell hacks and write a util in C instead. > Thanks Maciej for pointing out Makefile variable problem. > > v4: Finally we managed to find a Makefile method to do it properly > thanks to Kees. As it's too far from the initial version, I removed > Review & Test tag from Nick and Fangrui and Cc instead. > --- > arch/mips/Makefile | 12 +++++++++++- > arch/mips/kernel/vmlinux.lds.S | 2 +- > 2 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/Makefile b/arch/mips/Makefile > index e1c44aed8156..18495568f03e 100644 > --- a/arch/mips/Makefile > +++ b/arch/mips/Makefile > @@ -288,9 +288,19 @@ ifdef CONFIG_64BIT > endif > endif > > +# When linking a 32-bit executable the LLVM linker cannot cope with a > +# 32-bit load address that has been sign-extended to 64 bits. Simply > +# remove the upper 32 bits then, as it is safe to do so with other > +# linkers. > +ifdef CONFIG_64BIT > + load-ld = $(load-y) > +else > + load-ld = $(subst 0xffffffff,0x,$(load-y)) > +endif > + > KBUILD_AFLAGS += $(cflags-y) > KBUILD_CFLAGS += $(cflags-y) > -KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) > +KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) -DVMLINUX_LINK_ADDRESS=$(load-ld) > KBUILD_CPPFLAGS += -DDATAOFFSET=$(if $(dataoffset-y),$(dataoffset-y),0) > > bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) \ > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index a5f00ec73ea6..5226cd8e4bee 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -55,7 +55,7 @@ SECTIONS > /* . = 0xa800000000300000; */ > . = 0xffffffff80300000; > #endif > - . = VMLINUX_LOAD_ADDRESS; > + . = VMLINUX_LINK_ADDRESS; > /* read-only */ > _text = .; /* Text and read-only data */ > .text : { > -- > 2.26.0.rc2 >
This version does not quite work:
ld.lld: error: section .text at 0xFFFFFFFF80990000 of size 0x388C exceeds available address space ld.lld: error: section .MIPS.abiflags at 0xFFFFFFFF80993890 of size 0x18 exceeds available address space ld.lld: error: section .rodata.str1.1 at 0xFFFFFFFF809938A8 of size 0x164 exceeds available address space ld.lld: error: section .eh_frame at 0xFFFFFFFF80993A0C of size 0x2C exceeds available address space ld.lld: error: section .data at 0xFFFFFFFF80993A40 of size 0x38EFD0 exceeds available address space ld.lld: error: section .got at 0xFFFFFFFF80D22A10 of size 0x8 exceeds available address space ld.lld: error: section .bss at 0xFFFFFFFF80E22A20 of size 0x402010 exceeds available address space ld.lld: error: section .sbss at 0xFFFFFFFF81224A30 of size 0x8 exceeds available address space make[2]: *** [/home/nathan/src/linux/arch/mips/boot/compressed/Makefile:104: vmlinuz] Error 1
I think something like this is needed but I do not know if it is proper.
Cheers, Nathan
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 18495568f03e..68c0f22fefc0 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -304,6 +304,7 @@ KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) -DVMLINUX_LINK_ADDRESS=$(loa KBUILD_CPPFLAGS += -DDATAOFFSET=$(if $(dataoffset-y),$(dataoffset-y),0) bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) \ + VMLINUX_LINK_ADDRESS=$(load-ld) \ VMLINUX_ENTRY_ADDRESS=$(entry-y) \ PLATFORM="$(platform-y)" \ ITS_INPUTS="$(its-y)" diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile index 0df0ee8a298d..3d391256ab7e 100644 --- a/arch/mips/boot/compressed/Makefile +++ b/arch/mips/boot/compressed/Makefile @@ -90,7 +90,7 @@ ifneq ($(zload-y),) VMLINUZ_LOAD_ADDRESS := $(zload-y) else VMLINUZ_LOAD_ADDRESS = $(shell $(obj)/calc_vmlinuz_load_addr \ - $(obj)/vmlinux.bin $(VMLINUX_LOAD_ADDRESS)) + $(obj)/vmlinux.bin $(VMLINUX_LINK_ADDRESS)) endif UIMAGE_LOADADDR = $(VMLINUZ_LOAD_ADDRESS)
| |